Posted
by
samzenpus
on Thursday January 23, 2014 @03:57AM
from the plenty-of-time dept.

sciencehabit writes "Take a deep breath—Earth is not going to die as soon as scientists believed. Two new modeling studies find that the gradually brightening sun won't vaporize our planet's water for at least another 1 billion to 1.5 billion years—hundreds of millions of years later than a slightly older model had forecast. The findings won't change your retirement plans but could imply that habitable, Earth-like alien worlds are more common than scientists thought."

Lecturer:.... and in 1 billion to 1.5 billion years the sun will vaporise all the oceans...Student: What!Lecturer: I said that in around 1 billion to 1.5 billion years...Student: Oh! That's a relief, I thought you said Million!

They should have kept this secret and stuck with the earlier prediction as a deadline for getting off this planet. Then, when it turns out we're not actually ready yet by that time, you can give us the relieving "ok, you've got another few hundreds of millions of years but that's final". Our species is notoriously bad at making deadlines.

It's an input to the Drake equation. That's worth looking at again.
When Drake wrote it, most of the numbers were guesses, but we now know that exoplanets are not rare.

I suspect the reason we haven't heard from anybody is that the lifetime of high-power technological civilizations is only a few hundred to a thousand years. We're only about 200 years into industrial society, and we've already burned through most of the easy to get natural resources.

Assuming you are looking for RF, rather than UFOs, even short lived civilizations should show up, just as some of the stars that are presently visible to us are in fact long dead; but very far away.

This would be immensely frustrating, of course, since virtually any signal you receive would be from a civilization that is either already dead or will already be dead by the time your reply, if you wish to attempt one, reaches them; but it would still be distinguishable from silence.

but think of it as a circular wave that emanates from a planet, like a circular expanding donut [the inside=death of the planet or they've moved on]. what are the odds that that wave just happens to be passing by us now that we have the capability of possibly noticing it?

It actually get's worse. The "why haven't we heard from them" paradox was based on the fact that in the 60s scientists could not imagine an advanced civilization without strong RF emissions. But we are already strongly dialing back the RF emissions by putting more onto wires, using more directed beams and lower power emissions. This overall means that in a couple of decades the earth will not emit any decipherable RF transition, either since most RF has died out or because you can not make out a signal from

IIRC, the brightest man-made electromagnetic sources are over-the-horizon radars [wikipedia.org]. I think the use of them will drop off much slower than the use of RF for information. The signal will show a 24 hour cycle due to the rotation of the earth. That means that the detecting intelligent life on Earth will be possible for a longer time, though deciphering messages will not be possible.

If you think the uplinks to the Geostationary satellites are low power and dont spread out, you really dont understand RF or satellite comms. Some of the older TV birds up there are almost deaf, so we are BLASTING 100,000 watts of energy into a 25 to 30 db gain antenna to hit them. when the signal hits it, it is not 3 inches around and fits nicely in the receiving antenna, it's about 5 miles across, and will continue to spread.

Here is the problem. Radio waves drop in strength Logarithmically. Which means even a 100,000 watt tightly beamed RF signal will be barely above the noise floor before it even get's 4X the diameter of our solar system away. When they talk to Voyager 1 or 2 they are using the largest dish antenna on the planet, and then they are blasting an ungodly amount of power to barely reach it. They also are using the 8GHZ band that has a very low noise floor and almost no interference within a lightyear.

Voyager has a 23 watt transmitter, but a large gain antenna focusing it at earth, but it requires the massive 1000 foot dish or a huge array of smaller dishes to barely receive it. and not much longer, we will not have an antenna with enough gain on this planet to receive it's signal any longer. within the next 4-5 years we are expected to lose all contact with Voyager 1. And this thing is just in out back yard a few feet from the house.

Even if an alien race knew where earth was exactly, and had a 1000 foot dish antenna with a 10Terawatt transmitter pointed right at us. If they were not within a 20 lightyear radius of the earth, their signal would not reach us at a strength that we could detect today.

Even if an alien race knew where earth was exactly, and had a 1000 foot dish antenna with a 10Terawatt transmitter pointed right at us. If they were not within a 20 lightyear radius of the earth, their signal would not reach us at a strength that we could detect today.

Never mind just 'today'. I vaguely recall someone publishing a proof that beyond a certain disappointingly small radius, any RF signal originating from earth is mathematically impossible to distinguish from background noise.

Unless we invent some serious technology to dig that signal out of the noise, you are 100% correct. Even insane gain levels on the antennas have a diminishing return. At a certain point, you end up amplifying the noise and making it all worse.

This is the scientific reason why SETI is a waste of time, Only someone cruising by below the speed of light within that very small radius even have a chance at hearing us.

Well, "easy" is relative. Replace "easy" with "cheaply" and you're closer to reality.

Take oil for example. 50 years ago the prediction was that 20 years later (i.e. 30 years ago), crude oil is a thing of the past. Well, there still is some. There's oil sands for example, something nobody would have even considered interesting 50 years ago due to far cheaper deposits being available. Well, now that the barrel broke through the 100 bucks barrier, other sources, more expensive sources, become viable.

For example, I have seen a documentary where scientists are starting to consider digging up metals, such as copper from old garbage dumps. It the price for these resources makes this viable, it will be done. Same goes with all things "green", if the cost/benefit ratio makes it viable, it will be widely adapted.

The situation that just infuriates me is the disposal of so-called 'nuclear waste' - if the government and greenies didn't have their collective heads up their butts we'd be burning that 'waste' in reactors that can extract the remaining 99% of the energy that was present in the original fuel. Instead we're going to vitrify it and bury it away.

The documentary was old that is already being done. There is also a recycler here that advertises they will come out and pick up refrigerators and other items for free that the city charges extra to dispose of.

I suspect the reason we haven't heard from anybody is that the lifetime of high-power technological civilizations is only a few hundred to a thousand years. We're only about 200 years into industrial society, and we've already burned through most of the easy to get natural resources.

Not really. We're just too stupid to reprocess nuclear waste, or build breeder reactors, in the U.S.. France isn't that stupid.

And out people are so obsessed with making money just to spend it on personal pleasure that we're not preparing for a future of mining for resources on distant planets and moons. How many big business people at Davos will be discussing this?

A factor of 1.5 won't matter for the drake equation, hell, a factor of 1000 is inconsequential. The only relevant parts are fl and fi (chance of life, and chance of life evolving into intelligent life), and we will never find them out even in approximation.

The chance of life parameter is very measurable. We can now find the spectrum of exoplanet atmospheres. A dead giveaway of life is free oyxgen; ever find free oxygen in the atmosphere of an exoplanet and it's sure to have a biosphere. Free oxygen reacts too quickly with just about everything to be caused by geologic processes. Sure, this approach won't find those planets with life that does not run on oxygen, but it will find those with a biochemistry somewhat similar to our own.

The only relevant parts are fl and fi (chance of life, and chance of life evolving into intelligent life), and we will never find them out even in approximation.

You use the word "never" in a thread about events on a geological and/ or astronomical timescale? The only way you could be serious about using that word could be if you expect our species to become extinct before we get an answer to the question "is there other intelligent life in this galaxy". Which I guess is possible, but pretty pessimistic.

I suspect the reason we haven't heard from anybody is that the lifetime of high-power technological civilizations is only a few hundred to a thousand years.

Alternatively, after multiple millennia of exo-christians predicting the end of the world, space Jesus raptured everyone just to get them to STFU and that's why we haven't heard from any alien civilizations yet.

The drake equation does not take into consideration that most civilizations destroy themselves when they achieve the point of being able to communicate. We are at that point right now, we may simply wink out in a large war in the next 50 years. but if we make it past that 50 year point we will have the technology to much more, unless we create a new super weapon, then the cycle starts all over.

Because as a species we are not very evolved. We gladly kill each other over really stupid shit.

The drake equation does not take into consideration that most civilizations destroy themselves when they achieve the point of being able to communicate

One other point... we have a data set of less than one to work with, ourselves. I do not think that we can extrapolate based on our experience. Can we say with any kind of certainty that other species would follow a similar evolutionary path as ours? Would a smaller planet result in a slower evolutionary process and less global conflict once intelligence does

All the species on this planet are hell bent on destruction and killing. Trees choke out competing trees, animals eat each other, Humans are evil horrible creatures that care only about themselves and their own goals....

In fact we have no species at all on this planet that is 100% benevolent. All of them are violent and destructive in their own way.

That is assuming that intelligent life did evolve. We as human species were extremely lucky. There were at least 5 mass extinction in the pass, killing about 98% of all species every time. About 99% of all species existed went extinct on earth. Who knows how life would have evolve if the dinosaurs did not went extinct, giving way for small rodent-like mammals that evolved in primates and ultimately in us. Also if the land mass would be slightly different we couldn't have emigrated out of Africa, probably wo

Even if there weren't mass extinctions to worry about, the odds are still stacked against intelligent life. Out of all the species on Earth there are only a handful with opposable thumbs and the intelligence to use tools alive today. There were even less than that at any time that were intelligent enough for language and to make tools from more than one material, much less any kind of advanced technology. Only one remains. So out of all the millions of species on the planet we have a few dozen that aren't "

That is true. For example Dolphins are quite intelligent and have a complicated language. But the simple fact that they life under water already limit their ability to become truly intelligent. For starters, like you said, they have fins and no fingers. To evolve fingers requite them to be put at a severe disadvantage for swimming and hunting fish. Also under water there is no chance ever to invent fire. So although dolphins maybe have the brains to be intelligent, they will probable never have an advance c

I suspect the reason we haven't heard from anybody is that the lifetime of high-power technological civilizations is only a few hundred to a thousand years. We're only about 200 years into industrial society, and we've already burned through most of the easy to get natural resources.

And when we manage to blow ourselves back to the stone age, we'll never be able to leave it without 'external' help - for the same basic reason, all the easy to access resources that made advances possible are gone.

Wood and fire is about all that will be left.

We've destroyed the natural water sources, removed biodiversity from plants. Are there any naturally occurring grains anymore?

And when we manage to blow ourselves back to the stone age, we'll never be able to leave it without 'external' help - for the same basic reason, all the easy to access resources that made advances possible are gone.

I agree that the using up of resources would be a problem for a re-emerging civilisation, but I don't think that it's quite as bad as you make out. what tends to happen is that early-established mines (oilfields, etc) tend to be exploited as technology has been expanding, but then are abandoned a

We can't even replace someone's arm or liver (yet), or predict weather out farther than a week or two (and not even that super reliably), and have a probe barely out of our single solar system and yet people take these megapredictions so srsly.

I find the work on how the universe was in the past or will be in the future fascinating, but would laugh at anybody trying to stake a serious claim on it being ultimately true. Sure, it may be possibly true, as well as all the predictions predicated on the big bang

No, read what I wrote again. More worried != worried, in the same way a isdn is faster than dialup, but neither are fast.

Just a few short decades ago, black holes weren't thought to exist and if they did, be rare things, now they are at the center of every galaxy playing a huge part in galactic formation. There is a lot of hand waving going on with dark matter and dark energy, which is code for "we don't know wtf is going on", so excuse my skepticism on the "simple physics" of it all.

I find the work on how the universe was in the past or will be in the future fascinating, but would laugh at anybody trying to stake a serious claim on it being ultimately true.

Well, it's a good thing that no scientists resemble your straw man. The scientists come up with an educated guess and test it, refining it as they go. Newton's laws still work great for lots of things, despite Einsteins curved space-time being a more accurate (but still wrong) formulation of reality. The very foundation of science itself is the notion that everything we know is not the ultimate truth.

The real question is how long conditions within human tolerance limits would last. The Mayans were wrong about 2012 (provided people who interpreted their writings weren't duped by a bunch of Mayan 'pot'-heads), but we can't deny the climate changes that have been unfolding the past few centuries, even if we factor in the effects of human industry. Has anyone done a study on just what period of Earth's existence sustained biological life? Is that important in understanding the possibilities of colonizing ot

"Has anyone done a study on just what period of Earth's existence sustained biological life?"

Yes, but the jury is still out on that one because most rock strata that were around billions of years ago have long since been subducted or eroded away taking any evidence of early life with them. Plus single cell organisms don't fossilize well.

Shouldn't be impossible to graphically estimate the onset of life from its expansion from the earliest recorded fossils. Given that Earth's been around 4.5 billion years and now is projected to be around for another billion, an error of a million or so years wouldn't be an issue. BUT, the remainder of a billion years in it's existence, only a fourth of how long it has already been around, does beg the question as to what the life-sustaining window is.

If his model is based on where continents and oceans are now it could well fail to predict what might happen in a billion years time. If there's more ocean around the equator in the future it could drastically increase how much heat earth absorbs, similarly if another giant continent such as Pangea forms there could be a huge desert in the centre reflecting back heat. Of course that also means less plant life so possibly less CO2 being absorbed etc.

Yes, I'm sure that the computational physics that performed the research must have overlooked one of the simplest principles of numerical modelling in performing the research. I'd love to hear your insights into the Rosetta mission. "That's not a comet, that's clearly just a smudge on the lens. They obviously forgot to clean the probe after they made it."

Yes, I'm sure that the computational physics that performed the research must have overlooked one of the simplest principles of numerical modelling in performing the research. I'd love to hear your insights into the Rosetta mission. "That's not a comet, that's clearly just a smudge on the lens. They obviously forgot to clean the probe after they made it."

I LOL, there's a difference between adjusting for the present than predicting something millions of years from now when solar dynamics are being updated regularly.

Yeah, and out of all the things that could possibly go wrong, you decided to suggest the most blindingly obvious thing that anyone involved in their kind of work would have been testing for since day one.

Yeah, and out of all the things that could possibly go wrong, you decided to suggest the most blindingly obvious thing that anyone involved in their kind of work would have been testing for since day one.

Your not making sense, this is an article about the Sun and your talking space craft.

There are other limiting factors eventually causing life to go extinct. One important is CO2 which is absorbed into the oceans and recirculated by volcanic activity driven by radioactivity. Radioactivity will cease in about 500 mio yrs, IIRC, which is when life will end due to scarcity of CO2.

Even the most dire predictions don't forecast climate change ending all life on Earth. Here's a sample worst-case scenario [usatoday.com]. It's bad, not as bad as the effects of a widespread nuclear war or an impact from a moderately sized asteroid, but bad enough to warrant spending a few percent of our GDP to avoid the worst scenarios of global warming.

A Princeton-led research group has discovered [princeton.edu] an isolated community of bacteria nearly two miles underground that derives all of its energy from the decay of radioactive rocks rather than from sunlight. According to members of the team, the finding suggests life might exist in similarly extreme conditions even on other worlds.

The Sun's increasing luminosity begins to disrupt the carbonate–silicate cycle; higher luminosity increases weathering of surface rocks, which traps carbon dioxide in the ground as carbonate. As water evaporates from the Earth's surface, rocks harden, causing plate tectonics to slow and eventually stop. Without volcanoes to recycle carbon into the Earth's atmosphere, carbon dioxide levels begin to fall.[30] By this time, they

I'm pretty sure that what they're talking about relates to this. A lot of estimates that have been made in the last few years said that our volatiles would burn off in 500 million years. This is just a new estimate.

That of course assumes that life will not adapt to the new conditions.

I expect that as carbon dioxide gets lower, plants will evolve new methods to get to the necessary carbon. Some probably will evolve the ability to extract carbon bound in rock. I can also imagine new symbioses where plants live directly on animals, extracting their CO2 directly from the lungs, so it doesn't enter the atmosphere where it could be captured by rock (of course the actual reason will be that CO2 concentration in the lungs is

CO2 is gradually being absorbed into limestone by biological processes. It has fallen from 90% 4 GY ago to 1% 1/2 GY ago to.03% just before the industrial age. Photosynthesis and multicellar life terminates at.01%.

Burning limestone, i.e. done in cement manufacture, would return ample CO2 to the atmosphere. Cement manufacture accounts for about 10% current CO production. I am asssuming that hydrocarbon energy combustion is a transient phenomena, unlikely to continue more than a few more centuries aft

Can we similarly tweak with Mars to make it more habitable, or will moving its orbit too close to Earth mess up Earth's orbit? What about a carefully-timed angled orbit such that it's never near Earth?